ALBUQUERQUE, N.M. — In-person classes have been canceled at a local charter school for the rest of the week after the roof of its new gym collapsed.
School officials say the new gym at the Explore Academy middle and high school campus was basically complete. They were even planning on hosting a ribbon cutting Wednesday, but that’s been canceled, as well as all in-person classes.
Parents learned about the collapse through an email from the school Sunday night.
“The students are out the whole week now,” a parent told KOB 4 anonymously. “Because they have to get inspectors to gather and, at the request of the inspectors in particular, for students to stay away until they can just look the whole thing over.”
The parent said the incident has raised many more concerns about sending her child back to school.
“Students were going to be in that building in two days, and I think one of the big questions I personally have is, did it pass the inspection already?” the parent asked.
The answer is no. KOB 4 spoke with a rep from Albuquerque’s Planning Department. They said the construction company, AIC General Contractors, failed a building frame inspection on March 6. Inspectors found the trusses bowing or bending.
The city’s Planning Department didn’t know the roof had caved in until KOB 4 called Monday afternoon.
Explore Academy leaders say, as of now, it’s just the new gym that seems to be impacted, but they aren’t taking any chances.
“They discovered the damage and evaluated the situation and decided that we would go ahead and go to asynchronous learning until we have a sign off that the entire building and structure is, in fact, safe for students to enter,” said Katia Pride, Explore Academy’s director of outreach.
Pride said there was no obvious damage to nearby classrooms. The school will also have to bring in an engineering company to create a repair plan.
The city’s Planning Department will be sending a building complaints investigator to figure out what went wrong.
1) It is unlikely that any lateral restraint of the truss chord existed within the bearing area.
2) From the aerial images, it doesn't appear that any studs were added to the top chord to tie the truss to the roof sections. I'm guessing the red that we see is simply the unpainted truss. It looks like after installation the truss was painted grey.
So a question I have is, Aren't the roof panels supposed to span (in the N-S direction from above) between the concrete block wall and the truss, and then between the trusses? If so, why do we not see in the failed image the truss that remained in place? It appears that there is an overhang. Is this just an optical illusion? You would expect that the roof would fail/crack along the center line of intact truss. From the image below it appears that some portion of the full roof panel is visible to the S of the truss. For reference I drew a line between the corners of the windows.
TheGreenLama - the planks failed with the truss, but there's probably a seam in the roofing material where it separated that doesn't line up with the structure. I'd guess the structure fell away but the roofing is still clinging together in those shots.
It does appear as tomh has pointed out, that the top inner portion of the pilaster has failed.
If the dip reported is deflection of truss, it appears that would lessen effective top cord bearing surface area, and thus put increased bearing pressure at the inner edge of pilaster.
You would expect that the roof would fail/crack along the center line of intact truss ... For reference I drew a line between the corners of the windows.
You can see a break line on the roof where the intensity goes from bright white to duller white near the edge of remaining roof portion on the left. The intact truss is at the intensity transition, which is consistent with the 3 windows being bracketed by the pilasters holding up the trusses.
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!
phamENG - I suspect you are correct. As mentioned above, on top pf the precast panels there could have been additional insulation, a topping layer, and a membrane. Maybe what we see are a straight line seam in the membrane, with pieces of insulation hanging down. Not parts of the precast panel.
There is a V kink in the truss/roof membrane, creating a saddle. The vertex of the saddle appears to be approximately in line with the square station (i.e., the segment lacking a diagonal). There appears to be gross deflection of the truss with the flexure point at this location. Under what circumstance would this disfigurement occur?
I suspect the fold in the roof sheeting is simply the cantilevering sheeting sagging over the truss line; The fold disappears near the ends of the truss because the sheeting is being held up by the walls here. The sheeting cannot fold down like it does at the middle of the truss.
A typical detail option for the welded end of a steel joist, bearing on a masonry block wall. This concept design detail indicates that steel joist should have not been in direct contact with block pilaster (especially the masonry edge of pilaster block). All bearing area should be located on the poured bond beam.
Masonry pilaster damage could have happened as joist deflected, and pulled joist downward and away from bond beam bearing area, and as joist dropped to lower energy state.
Was the suggested 10" block wall too small in depth for required minimum bearing area of large long span steel truss? Thus pilaster added to increase bearing area, and perhaps placed some bearing area all the way to edge of block? Perhaps a Value Engineering offering from Builder to save money on 12" block without pilaster? This also places horizontal rebar further away form edge of block wall bond beam.
Similar could HVAC units have been located on ground running thru steel truss openings, and GC offered Value Engineering approach to change that after steel truss ordered?
I know customers make a lot of demands after project bids are over budget, to bring them back into budget..and of course for other hard to understand reasons....
Duct work running with hollow concrete planks, concentrates all that load on one or two planks, whereas crossing perpendicular to run of planks spreads large mechanical loads across many planks. Probably not enough load to matter, but those large toggle bolt looking holes in the threaded rod picture bones posted sure looks like an incorrect anchor for hollow core planks, according to a quick look on Hilti's hollow core anchor site.
Still wild to see a pretty-much-finished building have a sudden collapse on a regular night with no live loads. I always say "buildings just don't fall down", but I might have to add the caveat "except when they do".
Agree, however I imagine thermal changes in roof materials vary a lot in Albuquerque from Hot Clear Days, to dry cool nights. So thermal could be a factor in timing of drop.
In the pictures posted, it appears the sides of hollow core panels fit tightly against the inside face of block wall. No ledge to sit on.
that steel joist should have not been in direct contact with block pilaster (especially the masonry edge of pilaster block). All bearing area should be located on the poured bond beam.
I guessed at the block size. It could be 12". Again, need plans.
Pilasters are used exactly for this reason all the time. The truss reaction is in the realm of 140kip or more. That is not the type of load you put on a simple block wall in most cases given the wall height.
I don't think the wall is the problem here. From the newer pictures it seems they managed to get the trusses where they were supposed to be. The question is why did the trusses fall off? Unless there are some very good connections our internet sleuths have not found, I would lean towards a LTB failure.
